(INDIRA) Call Girl Aurangabad Call Now 8617697112 Aurangabad Escorts 24x7
TAMU MEEN 475 CAES Term Project Presentation
1. December 7th, 2016
MEEN 475 – 502
Section Instructor: Dr. Tanil Ozkan
Team
Gus Gremillion
Ryan Gautier
Nick Albert
Jacob Walter
Serdar Ozguc
Cory Lusk
Zach Gregory
Compressed Air Energy Storage
2. Introduction - Compressed Air Energy Storage (CAES)
• CAES is an alternative form of energy storage to
fossil fuels and chemical batteries
• Up to 30 year lifespan with minimal
environmental impact
• Current implementations – Storage in large
underground salt caverns
• No small-scale systems currently in use
• Issue: Diabatic compression produces low
efficiency values
• Solution: Improve storage efficiency by
reducing thermal losses
• Objective: Perform materials selection for a
household-scale adiabatic CAES system
[2]
3. System Specifications
• Energy capacity: 7.2 kWh
• 12 hour household consumption
• 2 components
• Load-bearing pressure vessel shell
• Yield Failure SF = 4 (typical of pressure vessels)
• Thermal insulation
Storage
Tank
Compressor
(Adiabatic Compression)
Electric
Power
Valve
Outlet to turbine
(electric power) or drive
shaft (mech. power)
Thermal energy loss
through tank shell
4. Temperature Requirements
• Internal temperature = 675°C
• Adiabatic compression
• Yield Failure SF = 4
• Minimum Insulation Service
Temperature = 675°C
• Minimum Shell Service
Temperature = 300°C
• Permits consideration of
most steels
[1]
5. Shell Material Selection
Function ● Pressure Containment
Constraints ● Ensure leak before yield failure
or fracture failure
● Radius-Thickness Ratio = 10
● Operating Temperature ≥ 300°C
Objective ● Maximize Safe Internal Pressure
● Minimize Shell Thickness
Free
Variables
● Material
● Wall Thickness
[1]
6. Thermal Insulation Material Selection
Function ● Thermal Insulation
Constraints ● Operating Temperature = 675°C
Objective ● Minimize Thermal Energy Losses
Free
Variables
● Material
● Wall Thickness
[1]
8. AHP Results
Shell Material:
• SA516-70 Steel has the highest score, however 304 Stainless
Steel is close and have higher operating temperature. With
Stainless Steel, insulation can be placed outside the vessel.
Insulation Material:
• Fiberfrax S Durablanket wins, mainly due to low thermal
conductivity.
Material properties from: [4, 5, 6, 7, 8, 9, 10, 11, 12]
9. Shell Manufacturing Process Selection
Process
Shape
Flat Sheet
Dished Sheet
Mass
1000-2000 kg
Section
Thickness
40-70mm
Economic Batch
Size
~1000 Units
Sand Casting X ✔ ✔ ✔
Die Casting X X X X
Investment Casting X X X ✔
Forging X ✔ ✔ ✔
Sheet Forming ✔ X X X
Powder Methods X X X X
Electro- Machining X X X X
Conventional Machining ✔ ✔ ✔ ✔
[1]
10. Preliminary Calculations
• Assuming the vessel is designed with a radius-thickness ratio
of 10 and a yield safety factor of 4, the maximum allowable
pressure was found to be 7.25 MPa.
• The temperature of atmospheric air compressed
adiabatically was calculated to be 675 oC. Initial
temperature and pressure are taken from the room
condition.
11. Stress State Analysis
• Hoop stress and axial stress can be simplified with thin wall
assumption.
• Ductile materials tend to fail due to shear. Hoop stress and
axial stress are the principle stresses. Maximum shear stress
can be calculated.
• Shear strength of steels can be estimated by using their yield
strength. Estimated shear stress is higher than the maximum
shear by a factor of 9.28.
12. Vessel Joining: Welding
[13]
• The longitudinal welds take only
the the hoop stress from the
internal pressure; circumferential
welds take the tangential stress.
• Annealed properties of 304
stainless steel was used for the
stress state analysis, thus welded
joints are strong enough to carry
the hoop stress and the maximum
shear stress.
•Cylindrical shell will be joined
using double butt welds;
hemispherical heads will be joined
using lap welds.
[14]
13. Energy Analysis
• Energy required for 12 hours at a standard home is 7.2 kWh.
Using the pressure of 7.25 MPa and 675 oC, specific internal
energy of ideal air was found. Using density of air at 675 oC,
required volume was estimated to be 1.94 m^3.
• Using this volume and 0.6 m radius corresponds to a pressure
vessel length of 2.13 m.
• Radius to thickness ratio of 10 was used, thus wall thickness of the
shell is 6 cm.
• Resulting mass for the shell is around 3900 kg.
15. Future Work
• Design vessel to meet ASME Section
VIII Division 1 specifications
• Account for thermal stresses in vessel
• Account for irreversibility in air
compression and expansion
18. Shell Material Index Derivation
Stress Intensity of a crack:
Fracture stress limit:
Yield before break:
Max stress in thin-walled
pressure vessel:
Ductile failure
prevented if:
Allowable pressure:
19. Thermal Insulation Material Index Derivation
Heat
conduction:
Heat
stored:
Total heat
loss:
Total heat
loss:
Editor's Notes
Presenter - Wade
Presenter – Zach
Mention that with SF = 4 we are neglecting fatigue.
Presenter - Gus
Presenter – Ryan
Presenter – Cory
Presenter - Serdar
Need to add all tables and provide rationale for selecting stainless steel and the ceramic fiber blanket. In particular, note that with stainless steel the insulation can be placed on the exterior of the vessel; this simplifies manufacturing, maximizes the volume of air under compression, and reduces safety risks of people being burned by touching the exterior of the vessel.
Presenter - Serdar
![Introduction - Compressed Air Energy Storage (CAES)
• CAES is an alternative form of energy storage to
fossil fuels and chemical batteries
• Up to 30 year lifespan with minimal
environmental impact
• Current implementations – Storage in large
underground salt caverns
• No small-scale systems currently in use
• Issue: Diabatic compression produces low
efficiency values
• Solution: Improve storage efficiency by
reducing thermal losses
• Objective: Perform materials selection for a
household-scale adiabatic CAES system
[2]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)